Hidden compartments for super-secret or important documents are always fun to build, and Instructables user assemblyrequired managed to build this one inside of a quarter, modeled after the old secret coin compartments used by cold war spies.

You'll need to put in a little elbow grease to make this one work, but you'll need three quarters, a drill, a dremel, some hot glue, and some time. The goal is to make the coin hollow, so you're going to file down the top and bottom of one coin, and then hollow out the third so you essentially build a new coin from the top, ribbing, and bottom of three others. Assemble it all with a dab of hot glue so you can crack open one side when you need to, and you're done. If you're worried about legality, some of the commenters at Instructables debunk that pretty handily.

Advertisement

We'll be the first to admit that this isn't super-practical, and you'll spend 75 cents to get one quarter-sized container out of it, but it's still large enough to hold a microSD card or a tiny scrap of paper, and that's large enough to keep a treasure trove of important files. If you want to put all of your personal data on a microSD card and keep it somewhere it won't get stolen, a tiny quarter safe like this would fit right into your wallet, a pocket, a bag, or even in something stronger like a household safe or fireproof box. It'd also make for a fantastic addition to a cache, if you're into Geocaching. Hit the link below to see how to make one.